Asphalt-surfaced roadways are built to facilitate vehicular travel. Depending upon usage density, base conditions, temperature variation, moisture variation, and/or physical age, the surface of the roadways eventually become misshapen, non-planar, unable to support wheel loads, or otherwise unsuitable for vehicular traffic. In order to rehabilitate the roadways for continued vehicular use, spent asphalt is removed in preparation for resurfacing.
Cold planers, sometimes also referred to as road mills or scarifiers, are machines that typically include a frame propelled by tracked drive units. The frame supports an engine, an operator's station, and a milling rotor. The milling rotor, fitted with cutting tools, is rotated through a suitable interface by the engine to break up the surface of the roadway. The broken-up roadway material is deposited by the milling rotor onto a conveyor, or series of conveyors, that transport the material away from the machine and to a nearby haul vehicle for transportation away from the jobsite.
Control modules are provided in machines such as cold planers to operate the milling rotor and to control certain mechanisms associated with the machine. For example, the control module can control moving the milling rotor to a raised position when not in the milling mode, such as when the cold planer is moving in a direction reverse to the working (e.g., milling) direction.
Milling machines, such as cold planers can operate by making several parallel passes. It can be preferable to leave the milling rotor rotating when moving in reverse to prepare for the next pass because shutting down the milling rotor and starting it back up takes time and can cause wear and decreased life on the driveline. However, if the rotating milling rotor comes into contact with an object while the machine is moving in reverse, kickback created by the collision between the object and the rotating milling rotor can damage the machine and/or the object.
One attempt to address this issue is described in U.S. Pat. No. 7,530,641 to Berning et al., and issued on May 12, 2009. The '641 patent describes a construction machine that monitors the distance between a milling drum and a ground surface and uncouples the raised milling drum from a drive engine, or uncouples traveling devices from the drive engine, or raises the machine frame or generates an alarm signal when the monitoring device detects a deviation that falls below a pre-determined distance.
Although the '641 patent provides a way of preventing kickback created by the collision of the rotor with an object, the design may also have drawbacks because it is limited to detecting a distance between a milling drum and a ground surface to prevent kickback.
Another attempt to address this issue is described in U.S. Patent Application Publication 2016/0265174 to Engelmann et al, and published on Sep. 15, 2016. The '174 publication describes a control system having obstacle detection and mapping. The control system may include an obstacle detection sensor mountable to the cold planar at a location forward of the milling drum and also a locating device. The control system can use signals from the obstacle detection sensor and the locating device to generate an electronic map of a work area and to selectively adjust operation of the cold planer based on the electronic map.
Although the '174 publication includes obstacle detection, the control system in the '174 publication is limited to mapping the work area and does not sense or map in a manner that can prevent kickback.
The present disclosure is directed toward on or more of the problems set forth.